The invention provides nucleotide sequences coding for the glbO gene and a process for the fermentative production of L-amino acids, in particular L-lysine, using coryneform bacteria in which the glbO gene is amplified or enhanced. All references cited herein are expressly incorporated by reference. Incorporation by reference is also designated by the term xe2x80x9cI.B.R.xe2x80x9d following any citation.
L-amino acids, in particular L-lysine, are used in human medicine and in the pharmaceuticals industry, but especially in animal nutrition.
It is known that L-amino acids are produced by fermentation of strains of coryneform bacteria, in particular Corynebacterium glutamicum. Due to their great significance, efforts are constantly being made to improve the production process. Improvements to the process may relate to measures concerning fermentation technology, for example stirring and oxygen supply, or to the composition of the nutrient media, such as for example sugar concentration during fermentation, or to working up to yield the product by, for example, ion exchange chromatography, or to the intrinsic performance characteristics of the microorganism itself.
The performance characteristics of these microorganisms are improved using methods of mutagenesis, selection and mutant selection. In this manner, strains are obtained which are resistant to antimetabolites, such as for example the lysine analogue S-(2-aminoethyl)cysteine, or are auxotrophic for regulatory significant metabolites and produce L-lysine.
For some years, methods of recombinant DNA technology have also been used to improve strains of Corynebacterium which produce L-amino acids by amplifying individual biosynthesis genes for L-amino acids and investigating the effect on L-amino acid production.
Review articles on this subject may be found inter alia in Kinoshita (xe2x80x9cGlutamic Acid Bacteriaxe2x80x9d, in: Biology of Industrial Microorganisms, Demain and Solomon (Eds.), Benjamin Cummings, London, UK, 1985, 115-142) I.B.R., Hilliger (BioTec 2, 40-44 (1991)), Eggeling (Amino Acids 6:261-272 (1994)) I.B.R., Jetten and Sinskey (Critical Reviews in Biotechnology 15, 73-103 (1995)) I.B.R. and Sahm et al. (Annuals of the New York Academy of Science 782, 25-39 (1996)) I.B.R.
An object of the invention is to provide new measures for improved fermentative preparation of L-amino acids, in particular L-lysine. Amino acids, in particular L-lysine, are used in human medicine, in the pharmaceuticals industry and, in particular, in animal nutrition. Therefore, there is a general interest in providing new improved processes for the preparation of amino acids, in particular L-lysine. When L-lysine or lysine are mentioned in the following, not only the base but also the salts, such as e.g. lysine monohydrochloride or lysine sulfate, are also meant by this.
Any subsequent mention of L-amino acids or amino acids should be taken to mean one or more amino acids, including the salts thereof, selected from the group comprising L-asparagine, L-threonine, L-serine, L-glutamate, L-glycine, L-alanine, L-cysteine, L-valine, L-methionine, L-isoleucine, L-leucine, L-tyrosine, L-phenylalanine, L-histidine, L-lysine, L-tryptophan and L-arginine. L-Lysine is particularly preferred.
Any subsequent mention of L-lysine or lysine should be taken to mean not only the base, but also salts, such as for example lysine monohydrochloride or lysine sulfate.
The new DNA sequence of C. glutamicum which codes for the globin oxygen gene (glbO) and which as a constituent of the present invention is SEQ ID NO 1 and related sequences. The amino acid sequence of the corresponding gene product of the glbO gene has furthermore been derived from the present DNA sequence. The resulting amino acid sequence of the glbO gene product is SEQ ID NO 2 and related sequences.